Macrophage-Mediated Cytotoxicity

Abstract

Macrophages are among the most versatile and multifunctional of cells. Their phagocytic ability is an essential part of the nonspecific immune defense against microorganisms, and macrophages are also required for the specific immune responses, mediated by T and B cells, to occur. In addition, macrophages manufacture and release a wide variety of substances with many different functions (for a review, see Nathan, 1987). Perhaps the most remarkable thing about macrophages is their ability to differentiate between normal and transformed cells, and between normal and infected cells, and to selectively leave the normal cells unharmed while killing the transformed or infected cells (Fidler and Schroit, 1988). Thus, macrophages not only can discriminate between self and nonself, but also can often distinguish between normal and abnormal self. This chapter will examine the cytotoxic activity of macrophages against transformed and infected cells both in vivo and in vitro.